Patchcord connector



Nov. 24, 1964 R. .1. VANDERBILT PATcHcoRD CONNECTOR Filed NOV. l5, 1961INVENTOR. RICHARD J. VANDERBILT BY A Mw( ATTORNEY United States Patent O3,158,702 PATCHCGRD CONNECTQR Richard J. Vanderbilt, Rumson, NJ.,assignor to Electronic Associates Inc., Long Branch, NJ., a corporationof New Jersey Filed Nov. 15, 1951, Ser. No. 152,439 11 Claims. (Cl.20d-51) This invention relates generally to patchcord connectors and, inparticular, to a plug connector of the type used in patchboards forcomputers and the like for completing electrical circuits to control theoperation or" the computer as desired.

In the computer art, it is common practice to provide a plugboard orpatchpanel at which the various computing components may be selectivelyinterconnected by the use of patchcords. In the analog computer art, thedistributed capacitance of the patchcords, as well as the stray currentswhich may be picked up by the patchcords, contribute significantly tothe accuracy with which cornputations are performed and, therefore, ithas become a common practice to use shielded patchcords and providemeans such as the patchboard itself for eiiectively grounding theshields of the patchcord. In order to achieve this' end, the customaryanalog computer patchcord connector is adapted for completing a circuitconnection to a computing component while also completing a circuitbetween the braid or shield of a coaxial patchcord and the patchboard.

Prior art connectors of this type have been deficient in severalmaterial respects. The most noticeable and significant of the deciencieshas been that with continued use the connectors tend to become worn, titsomewhat loosely in the patchpanel, and fail to provide an adequatecircuit to ground for the shielded conductor of the patchcord. Also,being subject to continuous handling by the computer operators, theconnectors tend to accumulate the usual body oils found on the humanhand and other non-conductive dirt or foreign substances whichcontribnte significantly to the condition of poor electrical contactbetween the shield connector and the patchpanel. In order to eliminatethese conditions, it is frequently necessary to replace defectiveconnectors and to provide for the periodic cleaning of the connectors bythe use of carbon tetrachloride or other suitable cleansing solvents.

Prior art connectors further employ an uninsulated projecting terminal.Since it is quite common for computer operators to reconnect thepatchooard while the computer and patchcords are energized electrically,the uninsulated terminal is an ever-present hazard of shock to theoperators. Moreover, should the energized terminal be accidentallytouched to the grounded patchpanel, damage to circuit components orblown fuses will result.

The present invention is directed to a plug connector of the typedescribed which largely eliminates the deliciencies of prior artconnectors while also providing means to reduce the hazards associatedwith the handling of electrically energized terminals. `In its preferredform, the present connector comprises an elongtaed hollow insulatingsleeve member which is provided with plural longitudinal grooves oropenings. An electrical terminal extends outwardly of one end of thesleeve and is connected to a current-conducting wire of a coaxialconductor which is disposed within the sleeve. Another electrical termi-ICC nal may extend outwardly of the other end of the sleeve and providea connection to the wire braid or shield which is associated with thecoaxial conductor. An elongated sleeve member, which in the presentembodiment may be made of an electrical conducting material, is disposedcoaxially of the insulating sleeve, and the sleeves are biased forrelative movement in a direction to have the metallic sleeve normallycover or coaxially surround the current-conducting electrical terminal.Contact means, which may take the form of a current-conducting ball, aredisposed in each of the longitudinal openings in the insulating sleeveand are movable therein along their length upon movement of the sleevemember to complete an electrical circuit with the terminal which isconnected to the coaxial braid.

When the connector is removed from the patchboard, the metallic sleeveis moved in a direction to cover the current-conducting electricalterminal and prevent its being touched and thereby reduce the hazard ofelectrical shock to the operator. The hazard of touching the terminal tothe patchpanel is minimized by this arrangement and can be almostentirely eliminated by providing the terminal with an insulated tip.Upon the application of the slight pressure which is required to insertthe connector into a patchboard, the metallic sleeve is retracted touncover the current-conducting electrical terminal and make it availablefor completing an electrical circuit. When the connector is seated in anopening in the patchboard, the contact means are driven into engagementwith the wall portion of the patchboarcl opening by the means biasingthe normal relative movement of the sleeves in order to complete acircuit between the coaxial braid of the patchcord and the patchboard.

It is among the objects of this invention to provide a cover for aconnector terminal while it is disengaged and to permit the connectingof the terminal without having to employ additional means for uncoveringthe terminal while making it available.

Another object of this invention is to provide a cover for a connectorterminal while it is disengaged and to utilize the cover member forpurposes of completing a circuit between the coaxial braid of aconductor and a grounded patchboard when the connector terminal isuncovered and engaged.

A further object of the invention is to provide a patchcord connectorwhich is rugged enough to withstand rough handling and which has a longand useful life.

Still another object of the present invention is to provide a patchcordconnector of the type described which is relatively invulnerable to theadverse effects of surface contaminants.

These and other objects, features, and advantages will become apparentfrom the following description of a preferred embodiment of the presentinvention taken in connection with the accompanying drawings whereinFIG. v1 is a sectional View in elevation of a preferred embodiment of aplug connector embodying the features of the present invention as it ispartially withdrawn from an opening in the patchboard;

FIG. 2 is a view generally similar to that of FIG. 1 -but showing theplug -connector as it is fully inserted into an opening in thepatchboard; and

FIG. 3 is a view generally similar to FIG. 1 showing another embodimentof the present invention.

In the following description, like reference numerals 3 will be used todesignate like parts. In FIG. 1, the reference numeral 16 represents apatchboard which may be connected to an electrical ground and whichcontains a lplurality of openings such as 12, into which the plugconnector 14 is shown inserted. The connector 14 includes an outersleeve or barrel 15 which is preferably cylindrical in form and adaptedto be slidably received in one of the openings 12 as shown in FIGS. land 2. The rear end portion of the sleeve 15 has a shoulder 16 ofenlarged diameter to abut the front surface of the patchboard and limitforward movement of the sleeve inwardly of the patchboard. A pluralityof radially disposed openings 18 are provided in the sleeve adjacent tothe shoulder 16. The openings 18 are of circular form and taperedinwardly of the sleeve 15 in order to captively retain a contact element20, to be hereinafter described. An inwardly extending shoulder 22 isprovided at the front or forward end of the sleeve 15 to limit movementof the remaining elements of the connector, to be hereinafter described,relative to the sleeve. Although in this preferred embodiment of theplug connector, the sleeve 1S -is shown to be made of an electricallyconducting material such as brass, it can be made of an insulatingmaterial such as nylon or the like equally as well.

Disposed within the bore of the sleeve 1S and slidably movable thereinis a cylindrical insulating sleeve member 24 which may be made of nylonor the like. The member 24 is formed with a plurality of radiallydisposed slots or grooves 26 which correspond in number and radialposition to the radial sleeve openings 1S. Slots 26 extend along theaxis of the member 24 for a portion of its length and terminate in afront wall 28 and a rear wall 30. An axial bore 32 of suitable diameteris provided at the forward end of the member 24 and an axial bore 34 ofslightly larger diameter is provided at the rear end of member 24. Thebores 32 and 34 terminate at and define an insulating lian-ge 36internally of the ymember 24 which is provided with an axially disposedcylindrical aperture 38. The diameter of bore 34 is preferably selectedto be of the same diameter as the depth of slots 26 so as to permit thatportion of the slots which is disposed between a wall 30 and tlange 36to communicate with the bore 34. Member 24 is also provided with anenlarged rear end portion which may have a radial slot 40 adjacent toits for- Ward end.

Inserted within -the bore 32 is an elongated metallic terminal 42 whichmakes Contact with a suitable terminal 43 of 4the patchboard and whichhas a bullet-nose end extending outwardly of the member 24. Insertedwithin the bore 34 is another terminal 44 which may be generally in theform of a lsleeve and provided with a radial slot in lits outer surfaceadjacent to the end disposed within the bore 34. The radial slot mayoriginate at the corresponding end walls 30 when terminal 44 is fullyseated in the bore 34 and may extend in a generally forward direction todeiine a cam surface 46 within each of the slots or grooves 26. Thus, itwill be seen that the terminal 42 and the terminal 44 are insulated onefrom the other by the flange 36 formed by the insulating member 24. Inthis manner, terminal 42 inserted in bore 32 and terminal 43 inserted inbore 34- are secured in the cylindrical sleeve member 24 and aredisposed in a spaced end-to-end relationship within the insulatingsleeve 24.

In this preferred embodiment, contact element is generally in the formof a metallic ball, and one such element is disposed within each of theslots 26 with a portion of its surface normally extending upwardlyvthrough the corresponding radial openingI 1S. A spring 49 is disposedcoaxially of the insulating member 24 between its enlarged rear endportion and the shoulder 16 of ysleeve 15 to urge movement of the sleevein a direction to coaxially surround or cover the terminal 42.

The rear end portion of terminal 44 may extend out- Wardly of the bore34 and may be there provided with 'an enlarged diameter bore which maybe internally threaded. The portion of terminal 44 which lies within themember 24 may have a lbore of the same diameter as the aperture 38.

A typical coaxial conductor comprising a current-conducting element orwire 48 covered with a suitable dielectric and an external shield orbraid S0 is shown to be disposed within the plug connector 14. Thatpor-tion of the coaxial conductor which lies within the aperture 38 andwithin the same diameter internal bores of terminals 42 and 44 isstripped of its braid 50. The dielectric and lbraid are stripped fromthe wire 48 only for that portion of its length which lies within thereduced diameter bore of terminal 42. For convenience, the braid to Iberemoved from the conductor may be turned back open itself for thatportion of its length which lies within the enlarged bore of terminal 44when the coaxial conductor is fully inserted into the plug connector.

In securing the coaxial conductor -to the plug connector, it isconvenient to first push the conductor into the connector until theforward edge of the braid 50 engages the internally threaded portion ofterminal 44, and then twist or rotate the conductor relative to theconnector and thereby screw it inwardly thereof through coaction of thebraid and the internal threads to complete the insertion. In order toprovide for a rigid assembly and establish electrical contact betweenthe coaxial conductor and the plug connector, the terminal 42 may besuitably crimped at 52 and the terminal 44 may be suitably crimped at54. A suitable, commercially available plastic or rubberized insulatingsleeve 56 may be disposed coaxially of the rear end portion of member 24and Vfor a short length of the inserted conductor. Sleeve 56 may furtherbe secured to and seated in the radial slot 40.

When the plug connector 14 is withdrawn from an opening 12, the partsthereof assume the condition of FIG. l, viz., spring 49 biases thesleeve 14, and in turn the ball 2d for movement in a forward directionwhereby the sleeve provides a substantially complete cover for theterminal 42. Forward movement of sleeve 14 is limited by engagement ofballs 20 with the iront walls 28 of slots 26. In this position of thesleeve, the terminal 42 may be energized electrically and yet can behandled somewhat carelessly without presenting a hazard to the computeroperator. Moreover, in inserting an energized connector iuto an opening12 as shown in FIG. l, the danger of accidentally touching the terminal42 against the grounded patchboard is significantly reduced. It is alsoto be noted that in this position of sleeve 15 the balls 20 do notengage the terminal 44.

When the connector is being inserted into an opening in the patchboard1G as shown in FIG. l, the balls 20 extend beyond the cross-sectionlimits of the opening 12 and thereby engage the front surface of thepatchboard, adjacent to the opening 12. Continued inserting pressure onthe connector causes the balls 20 to roll or slide within the slots 25and permit limited unrestricted relative movement of sleeve 15 andinsulating member 24. When the relative movement of the sleeve 15 andinsulating member is such that the balls 20 descend the cam relativemovement of sleeve and insulating member 24 and cause the cam surface 46to press the balls 26 against the side wall portion of the opening 12.In this manner, a very satisfactory low-impedance circuit is establishedbetween the braid 5t) and patchboard lil via the terminal 44 and balls20. Moreover, since only a very small portion of a given ball is exposedto handling and since the balls normally rotate or wipe within the slots25, the low-impedance path established between the conductor braid andthe patchboard can be maintained over an extended period of continueduse with minimal maintenance. Since, in this embodiment, the sleeve 15does not form part of an electrical circuit for the coaxial braid, theaccumulation of dirt or other contaminants on its surface does notadversely affect operation or performance of the plug connector.

rl`he modification shown in FIG. 3 is similar to that shown in FIGS. 1and 2 except that the movable contact means are made as an integral partof the retractable sleeve and the terminal 42 is provided with abullet-nose tip 57 which is made of an insulating material, such asnylon. The tip 57 may be molded into an appropriate aperture provided inthe extending end portion of terminal 42 for this purpose.Alternatively, the aperture in terminal 42 and a portion of the tip 57may be provided with similar cooperative threads to facilitate theirassembly. Although the use of the tips 57 is shown only in conjunctionwith the embodiment of FIG. 3, it will be understood that it may be usedwith the embodiment of FIGS. 1 and 2 as well.

The retractable sleeve SS in the embodiment of FlG. 3 is preferably madeof resilient electrical-conducting material, such as a beryllium copperalloy. Although the sleeve may be formed by any suitable extruding ormetalforming operation, it has been found most desirable to form it froma flat rectangular sheet in a progressive die. While the sleeve 53 is inits flat form, it is provided with one or more pairs of longitudinalslits 59 which define a iinger or cantilever element du. Each finger orcantilever element 61B may be of a suitable length and of a width whichis somewhat less than the width of a corresponding openinU or groove 26.Through the use of a suitable die, each element or finger 5t) isthereafter altered in appearance so as to have a cross-sectionalconfiguration which is generally in the form of the letter S, whereby anarcuate portion 52 extends above the cross-sectional limits of the sheet58 and an arcuate portion 64 extends below the cross-sectional limits ofthe sheet. In the present embodiment, the arcuate portion 64 is formedadjacent to the free end portion of the finger or element du.

The sheet 58 may be thereafter rolled into the form of a slit sleeve andprovided with an inwardly extending radial lip portion 66 at the one orforward end and an outwardly extending radial lip portion 65 at itsopposite or rear end. The sleeve S8 thus formed is slipped over theterminal 42 end of insulating member 2d with the arcuate portions 64disposed for sliding movement in corresponding grooves or openings 25.

With the spring 49 biasing the sleeve 5S for movement in a direction tocover terminal 42, cooperation between the portions 64 and the bottom ofcorresponding openings 26 causes the arcuate portions 62 to extendbeyond the cross-sectional limits of the sleeve 53 and abut the frontedge portion of an opening l2 upon insertion of the plug connector ofthis embodiment into the patchboard. Engagement of the portions 54 withthe walls 23 limits relative movement of the retractable sleeve 58 andinsulating member 24 in one direction. Continued insertion pressure onthe plug connector permits movement of the sleeve 58 relative to theinsulating member 24 until such time as the portions 64 ride down thecam surface 46 and permit the arcuate portions 62 to be forced inwardlyof the cross-sectional limits of sleeve 58. At this time, the lipportion 68 may be moved into engagement with the front surface of thepatchpanel ltlto limit inward movement of the sleeve 58. Thereafter,when inserting pressure is removed from the plug connector, the spring49 will cause slight relative movement of the sleeve 58 and insulatingmember 24 to cause cam surfaces 46 to ress the portions 62 intoengagement with the sidewalls of the opening 12. A circuit is thusestablished between the braid 50 of a patchcord and the patchpanel 10via the linger or element 60, the arcuate portion 64 engaging theterminal 44 and the arcuate portion 62 engaging the patchpanel.

While in the embodiment of FIG. 3 the sleeve 58 forms part of anelectrical circuit between the braid of a coaxial conductor and thepatchpanel, the accumulation of dirt or other contaminants on itssurface is not signilicant because of the wiping action of the arcuateportions 62 and d4 on their respective contact surfaces. vantage of thisembodiment of plug connector over that of the embodiment shown in FIGS.1 and 2 is that the assembly of the components is somewhat simpler.Also, since there are fewer components to the plug connector in theembodiment of FIG. 3, its manufacture is somewhat less costly.

While the connectors and patchboard openings have been described asbeing of a cylindrical configuration, it will be apparent that thepresent connectors could be utilized in openings of other configurationsmerely by altering the external cross-sectional configuration of thesleeves 15 and 5S. In addition, although the present connectors havebeen shown and described for a particular use, it should be apparentthat a circuit for a conductor other than the braid of a coaxialpatchcord can be made with its use.

While only two embodiments have been shown and described herein, andinasmuch as this invention is subject to many variations, modications,and reversals of parts, it is intended that all matter contained hereinshall be considered as illustrative and not in a limiting sense.

l claim:

l. A plug connector comprising an elongated hollow insulating sleevehaving at least one longitudinal opening therein, a pair of metallicelements disposed in a spaced end-to-end relationship within saidsleeve, an elongated sleeve member disposed coaxially of said insulatingsleeve and movable with respect thereto along the longitudinal axisthereof, and a contact element disposed within said longitudinal openingand movable therein along the length thereof upon movement of saidsleeve member tolimit relative movement of said insulating sleeve andsleeve member in one direction and to establish electrical contact withone of said metallic elements upon relative movement of said insulatingsleeve and said sleeve member in an opposite direction.

2. A plug connector comprising a hollow cylindrical insulating sleevehaving a plurality of longitudinal openings therein, a pair of metallicelements disposed in a spaced end-to-end relationship within saidsleeve, a tubular sleeve member disposed coaxially of said insulatingsleeve and movable with respect thereto along the longitudinal axisthereof, and a metallic contact element disposed within each of saidplurality of openings and movable therein along the length thereof uponmovement of said sleeve member to limit relative movement of saidinsulating sleeve and sleeve member in one direction and to establishelectrical Contact with one of said metallic elements upon relativemovement of said insulating sleeve and sleeve member in an oppositedirection.

3. A plug connector comprising an elongated hollow insulating sleevemember having at least one longitudinal opening therein, a pair ofmetallic elements disposed in a spaced end-to-end relationship withinsaid sleeve, with at least one of said elements being disposed to extendoutwardly of one end of said sleeve, an elongated metallic sleeve memberdisposed coaxially of said insulating sleeve and movable with respectthereto along the longitudinal axis thereof, and a contact elementdisposed within said The ad- Y longitudinal opening and movable thereinalong the length thereof upon movement of said metallic sleeve to limitrelative movement of said sleeves in a first direction wherein saidmetallic sleeve surrounds said one outwardly extending metallic elementand to establish electrical contact with the other of said pair ofmetallic elements upon relative movement of said sleeves in an oppositedirection.

4. A plug connector according to claim 3 wherein said one metallicelement has a tip of insulating material on the end thereof whichextends outwardly of said insulating sleeve.

5. A plug connector comprising a hollow cylindrical insulating sleevehaving a plurality of longitudinal openings therein, a pair of metallicelements disposed in a spaced insulated end-to-end relationship withinsaid sleeve and extending outwardly of the opposite ends thereof, atubular metallic sleeve disposed coaxially of said insulating sleeve andmovable with respect thereto along the longitudinal axis thereof, and ametallic element disposed within each of said plurality of openings andmovable therein along the length thereof upon movement of said metallicsleeve to limit relative movement of said sleeves in one direction andto establish electrical contact with one of said metallic elements uponrelative movement of said sleeves in an opposite direction.

6. A plug connector comprising a hollow cylindrical insulating sleevehaving a plurality of longitudinal openings therein, a pair of metallicelements disposed in an insulated end-to-end relationship Within saidsleeve and extending outwardly of the opposite ends thereof, a tubularmetallic sleeve disposed coaxially of said insulating sleeve andincluding a plurality of radial openings therein, and a metallic contactdisposed within each of said plurality of longitudinal openings andextending into a corresponding one of said radial openings in saidmetallic sleeve, each said metallic contact being movable along thelength of a corresponding longitudinal opening upon movement of saidmetallic sleeve to limit relative movement of said sleeves in onedirection and to establish an electrical Contact with one of saidmetallic elements upon relative movement of said sleeves in an oppositedirection.

7. A plug connector comprising an elongated insulating cylinder having abore open at either end and having a plurality of longitudinal openingstherein, said cylinder having an inside shoulder intermediate its endsand an outside shoulder at one end, a metallic sleeve disposed in thebore at said one end of said cylinder and abutting said shoulder, ametallic stud disposed in the bore at the other end of said cylinder andhaving an end extending outwardly thereof, an elongated metallic barrelhaving a plurality of radial openings at one end and disposed coaxiallyof said other end of said cylinder, said elongated metallic barrelhaving a partially close-r end which is adopted to engage said one endof said cylinder to limit movement of said barrel in one direction andhaving an outer shoulder adjacent said radial openings, a springdisposed between said outside shoulder of said cylinder and said outershoulder of said metallic barrel for biasing said metallic barrel formovement in a direction to surround said stud, and a metallic ballcaptively retained within each of said plural openings in said metallicbarrel and a corresponding one of said longitudinal openings, each saidball being movable along the length ot said longitudinal opening uponmovement of said barrel to limit movement of said barrel in thedirection to surround said stud and for establishing electrical contactwith said metallic sleeve when said barrel is moved in an oppositedirection.

8. A plug connector for insertion within a plugboard opening ofpredetermined cross-sectional dimension, comprising a hollow cylindricalinsulating sleeve having at least one longitudinal opening therein, ametallic element disposed within said sleeve and including an inclinedouter surface within said sleeve juxtaposition said opening, a tubularmetallic sleeve disposed coaxially of said insulating sleeve and havingat least one radial opening therein, a metallic contact element disposedwithin said radial opening and movable along the length of saidlongitudinal opening, and spring means biasing said metallic sleeve andinsulating sleeve for relative movement in one direction with respect totheir longitudinal axes whereby said metallic contact is caused toextend through said radial opening beyond the cross-sectional limits ofsaid metallic sleeve, said metallic contact element engaging the frontsurface of the plugboard upon the application of pressure in insertingsaid metallic sleeve within the opening in the plug to cause relativemovement within the opening in the plugboard to cause relative movementof said insulating sleeve and said metallic sleeve in an oppositedirection, said contact element being driven into engagement with saidinclined surface by said spring means to complete an electr-ical circuitbetween said metallic element and the plugboard when the plug connectoris fully inserted into the plugboard opening.

9. A plug connector for insertion within a plugboard opening ofpredetermined cross-sectional dimension comprising a hollow cylindricalinsulating sleeve having at least one longitudinal opening therein, ametallic element disposed within one end of said sleeve and including aninclined outer surface within said sleeve juxtaposition said opening, ametallic stud inserted into the other end of said sleeve and having anend extending outwardly therefrom, a tubular metallic sleeve disposedcoaxially of said insulating sleeve and having at least one radialopening therein, a metallic contact element disposed within said radialopening and movable along the length of said longitudinal opening, andspring means biasing said metallic sleeve and insulating sleeve forrelative movement in one direction with respect to their longitudinalaxes, whereby said metallic contact is caused to extend through saidradial opening beyond the cross-sectional limits of said metallic sleeveand said metallic sleeve is caused to cover said stud, said metalliccontact element engaging the front surface of the plugboard upon theapplication of pressure in inserting said metallic sleeve within theopening in the plugboard to cause relative movement of said insulatingsleeveV and said metallic sleeve in an opposite direction, whereby saidstud is uncovered and said contact element is engaged with said inclinedsurface to complete an electrical circuit between said metallic elementand the plugboard.

l0. A plug connector comprising a hollow cylindrical insulating sleevehaving a plurality of longitudinal openings therein, a pair of metallicelements disposed in an insulated end-to-end relationship within saidsleeve and extending outwardly of the opposite ends thereof, and atubular metallic sleeve disposed coaxially of said insulating sleeve andincluding a plurality of radially disposed lingers, each of saidplurality of lingers being disposed within a corresponding one of saidplurality of longitudinal openings, said lingers being movable along thelength of a corresponding longitudinal opening upon movement of saidmetallic sleeve to limit relative movement of said sleeves in onedirection and to establish an electrical contact with one of saidmetallic elements upon relative movement of said sleeves in an oppositedirection.

l1. A plug connector for insertion into a patchboard opening ofpredetermined cross-sectional dimension, comprising a hollow cylindricalinsulating sleeve having a plurality of longitudinal openings therein, apair of metallic elements disposed in an insulated end-to-endrelationship within said sleeve and extending outwardly of the oppositeends thereof, a tubular metallic sleeve disposed coaxially of saidinsulatinlr sleeve and including a plurality of radially disposedS-shaped contact elements disposed for sliding movement in acorresponding one of said plurality of longitudinal openings, and meansbiasing said metallic sleeve for movement in a rst direction whereinsaid contact elements are caused to extend beyond the cross-sectionaldimensions of the patchboard opening and limit relative movement of saidsleeves, said sleeves being movable in an opposite direction uponengagement of said contact elements with the patchboard adjacent to theopening to establish an electrical circuit between one of said metallicelements and the patchboard.

References Cited in the le of this patent UNITED STATES PATENTS MannAug. 8, 1882 Prentiss Oct. 20, 1903 Williams Nov. 29, 1927 Block May 29,1956 FOREIGN PATENTS Germany Feb. 26, 1951 Great Britain June 9, 1943

1. A PLUG CONNECTOR COMPRISING AN ELONGATED HOLLOW INSULATING SLEEVEHAVING AT LEAST ONE LONGITUDINAL OPENING THEREIN, A PAIR OF METALLICELEMENTS DISPOSED IN A SPACED END-TO-END RELATIONSHIP WITHIN SAIDSLEEVE, AN ELONGATED SLEEVE MEMBER DISPOSED COAXIALLY OF SAID INSULATINGSLEEVE AND MOVABLE WITH RESPECT THERETO ALONG THE LONGITUDINAL AXISTHEREOF, AND A CONTACT ELEMENT DISPOSED WITHIN SAID LONGITUDINAL OPENINGAND MOVABLE THEREIN ALONG THE LENGTH THEREOF UPON MOVEMENT OF SAIDSLEEVE MEMBER TO LIMIT RELATIVE MOVEMENT OF SAID INSULATING SLEEVE ANDSLEEVE MEMBER IN ONE DIRECTION AND TO ESTABLISH ELECTRICAL CONTACT WITHON OF SAID METALLIC ELEMENTS UPON RELATIVE MOVEMENT OF SAID INSULATINGSLEEVE AND SAID SLEEVE MEMBER IN AN OPPOSITE DIRECTION.